An imaging element constituting an image sensor and the like has a structure of, for example, interposing a light-receiving layer (a photoelectric conversion layer) by two electrodes. Such imaging element includes a transparent electrode to which light enters usually constituted of a crystalline ITO. However, such transparent electrode has a large internal stress. This generates stress damage to the light-receiving layer, often deteriorating a characteristic of the imaging element. An imaging element (a photoelectric conversion element) to solve such problem caused by the internal stress from the transparent electrode has been well-known from, for example, Japanese Patent Application Laid-Open No. 2010-003901. That is, the imaging element (the photoelectric conversion element) disclosed in this patent publication includes a photoelectric conversion layer, which is disposed between a pair of electrodes, and at least one stress buffer layer, which is interposed between one of the pair of electrodes and the photoelectric conversion layer.
The stress buffer layer has a laminated structure including crystalline layers, specifically, a structure that laminates each two layers of the crystalline layers and amorphous layers (four layers in total) in alternation.